The following relates generally to wireless communication, and more specifically to access control. Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
Generally, a wireless communication network may include a number of base stations, NodeBs, or eNodeBs (eNBs) that can support communication for a number of user equipments (UEs). A UE may communicate with a base station via downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.
A UE may use a random access procedure when establishing or re-establishing a connection with an eNB. The random access procedure may include transmission of a random access preamble using a Physical Random Access Channel (PRACH). At some times, such as during emergencies, base stations may become overloaded with random access requests and may be unable to detect random access requests because of high interference on the PRACH. Similarly, overall traffic load in either uplink or downlink may be too high causing many request rejections. Reducing random access requests or overall traffic load while allowing access for users attempting to make important or critical communications can present challenges in multiple access environments.